Hellandite-(Y) Mineral Data

Hellandite-(Y) Mineral Data +

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General Hellandite-(Y) Information

Chemical Formula:

(Ca,REE)4(Y,Ce)2(Al,[ ])2[Si4B4O22](OH)2

Composition:

Molecular Weight = 1,029.47 gm

Calcium 11.68 % Ca 16.34 % CaO

Cerium 6.81 % Ce 7.97 % Ce₂O₃

La,Ce,Pr,Nd,Sm, 13.99 % RE 16.32 % REE₂O₃

Yttrium 12.95 % Y 16.45 % Y₂O₃

Aluminum 1.97 % Al 3.71 % Al₂O₃

Silicon 10.91 % Si 23.35 % SiO₂

Boron 4.20 % B 13.53 % B₂O₃

Hydrogen 0.20 % H 1.75 % H₂O

Oxygen 37.30 % O

______ ______

100.00 % 99.42 % = TOTAL OXIDE

Empirical Formula:

Ca₃REEY_1.5Ce_0.5Al_0.75(Si4B4O22)(OH)₂

Environment:

Pegmatite

IMA Status:

Valid Species (Pre-IMA) 1903

Locality:

Kragero, Telemark, Norway. Link to MinDat.org Location Data.

Name Origin:

Named for Amund Theodor Helland (1846-1918), geologist of Oslo, Norway.

Synonym:

Hellandite

ICSD 100145

IMA2000-F

PDF 25-184

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Hellandite-(Y) Crystallography

Axial Ratios:

a:b:c =4.0275:1:2.1845

Cell Dimensions:

a = 18.99, b = 4.715, c = 10.3, Z = 2; beta = 111.4° V = 858.66 Den(Calc)= 3.98

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2/a

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 2.63(1), 1.89(0.6), 2.82(0.6),

Crystal Structure:

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Mellini M , Merlino S , American Mineralogist , 62 (1977) p.89-99, Hellandite: a new type of silicoborate chain

Physical Properties of Hellandite-(Y)

Cleavage:

[001] Poor, [100] Poor

Color:

Green yellow, Grayish black, Reddish brown, Black.

Density:

3.7

Diaphaniety:

Translucent to subtranslucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

5.5-6 - Knife Blade-Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Greasy

Optical Properties of Hellandite-(Y)

Gladstone-Dale:

CI meas= 0.057 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.123 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1633,KPDmeas= 0.1757,KC= 0.1863

Optical Data:

Biaxial (+), a=1.64, b=1.65, g=1.66, bire=0.0200, 2V(Calc)=88, 2V(Meas)=80.

Calculated Properties of Hellandite-(Y)

Electron Density:

r_electron=3.51 gm/cc
note: r_{Hellandite-(Y)}=3.70 gm/cc.

Fermion Index

Fermion Index = 0.03981
Boson Index = 0.96019

Photoelectric:

PE_{Hellandite-(Y)}= 134.74 barns/electron
U=PE_{Hellandite-(Y)} x r_electron= 472.90 barns/cc.

Radioactivity:

GRapi = 21,088.75 (Gamma Ray American Petroleum Institute Units)

Hellandite-(Y) is Radioactive as defined in 49 CFR 173.403. Greater than 70 Bq / gram.

**Estimated Radioactivity from Hellandite-(Y)** - weak
Specimen Size Weight/Volume (Sphere) *	Calculated Activity Bequerols (Bq)	Calculated Activity Curies (Ci)	Estimated Activity GR(api)	Estimated Exposure (mRem**)/hr If Held in Hand For One Hour
1000 gm / 8.02 cm	466,887	1.26E-05	21,088.75	6.93
100 gm / 3.72 cm	46,689	1.26E-06	2,108.88	0.69
10 gm / 1.73 cm	4,669	1.26E-07	210.89	0.07
1 gm / 8.02 mm	467	1.26E-08	21.09	0.01
0.1 gm / 3.72 mm	47	1.26E-09	2.11	0.00
0.01 gm / 1.73 mm	5	1.26E-10	0.21	0.00
0.001 gm / 0.80 mm	0	1.26E-11	0.02	0.00

Weight of pure Hellandite-(Y) in grams (gm) and Calculated Diameter of a Sphere with a Density of 3.70 gm/cc.*
Goverment Estimate of Average Annual Exposure ( 360 mRem) **
Note: 10 microsieverts/hr = 1 mRem/hr **
Max Permissable Adult Dose 50,000 mRem/yr (hands), 15,000 mRem/yr (eyes)
Lethal Dose LD(50) Exposure 400,000 to 500,000 mRem
Estimated Thorium Activity ( 1.04 % Th) From Sum REE Elements (20.79 % REE)

Hellandite-(Y) Classification

Dana Class:

54.2.2.1 (54)Nesosilicate Borosilicates and Some Beryllosilicates

(54.2)with B in [4] coordination

(54.2.2)Hellandite group

54.2.2.1 Hellandite-(Y) (Ca,REE)4(Y,Ce)2(Al,[])2[Si4B4O22](OH)2 P 2/a 2/m

54.2.2.2 Tadzhikite-(Y)! Ca4(Y,Ce)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

54.2.2.3 Tadzhikite-(Ce) Ca4(Ce,Y)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

54.2.2.4 Hellandite-(Ce)! (Ca3REE)4Ce2Al[]2[Si4B4O22](OH)2 P 2/a 2/m

54.2.2.5 Mottanaite-(Ce)! Ca4(Ce,Ca)2AlBe2[Si4B4O22]O2 P 2/a 2/m

54.2.2.6 Ciprianiite! Ca4[(Th,U)(REE)]2(Al,[])2[Si4B4O22](OH,F)2 P 2/a 2/m

Strunz Class:

VIII/F.36-10 VIII - Silicates

VIII/F - Inosilicates (chain and band) complex chain structure. Cylindric chains and others

VIII/F.36 - Caysichite-(Y) - Tadzhikite-(Ce) series

VIII/F.36-02 Grumantite NaHSi2O5·(H2O) F dd2 mm2

VIII/F.36-05 Caysichite-(Y) Y2(Ca,Gd)2Si4O10(CO3)3(H2O,O,OH)·3H20 Ccm21 mm2

VIII/F.36-10 Hellandite-(Y) (Ca,REE)4(Y,Ce)2(Al,[])2[Si4B4O22](OH)2 P 2/a 2/m

VIII/F.36-15 Hellandite-(Ce)! (Ca3REE)4Ce2Al[]2[Si4B4O22](OH)2 P 2/a 2/m

VIII/F.36-20 Tadzhikite-(Ce) Ca4(Ce,Y)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

VIII/F.36-25 Tadzhikite-(Y)! Ca4(Y,Ce)2(Ti,Al,Fe,[])2[Si4B4O22](OH)2 P 2/a 2/m

VIII/F.36-30 Mottanaite-(Ce)! Ca4(Ce,Ca)2AlBe2[Si4B4O22]O2 P 2/a 2/m

VIII/F.36-40 Ciprianiite! Ca4[(Th,U)(REE)]2(Al,[])2[Si4B4O22](OH,F)2 P 2/a 2/m

VIII/F.36-60 Ashcroftine-(Y) K5Na5(Y,Ca)12Si28O70(OH)2(CO3)8·8(H2O) I 4/mmm 4/m 2/m 2/m

Other Hellandite-(Y) Information

References:

NAME( Ford32) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Hellandite-(Y) :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - EUROmin Project 4 -Google Images 5 -Google Scholar 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas 11 - Uranium Minerals

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Print or Cut-and-Paste your Hellandite-(Y) Specimen Label here :

Hellandite-(Y)

(Ca,REE)4(Y,Ce)2(Al,[ ])2[Si4B4O22](OH)2
Dana No: 54.2.2.1 Strunz No: VIII/F.36-10
Locality:

Notes: